Sellers are allowed to edit listings and to repurpose old listings to sell different items; that should have no effect at all on your purchase. If there is a problem and the item you receive is not as originally described, the seller cannot get out of a "Not As Described" case by pointing to a listing that was edited after the purchase.
If you go to your purchase history and view the item, you should see a banner at the top that says something to the effect that "the seller has changed the listing since your purchase -- click here to see the original item".
